On December 30th we asked
POST 101. December 30, 2020.CORONAVIRUS. Is there a point where the increasing Coronavirus trajectory so far exceeds the slow growth of the vaccination rate that reaching herd immunity through vaccinations becomes less likely? (A)
Here’s one answer.
“The coronavirus pandemic in the United States has raged almost uncontrollably for so long that millions of vaccinations will not be able to stop the spread of the disease unless people continue to wear masks and maintain social distancing measures until midsummer or later, according to a new model by scientists at Columbia University.
The arrival of highly effective vaccines in December lifted hopes that they would eventually slow or stop the spread of the disease through the rest of the population. But vaccines alone are not enough, the model shows. And if precautions like working remotely, limiting travel and wearing masks are relaxed too soon, it could mean millions more infections and thousands more deaths….
There is no doubt that getting vaccinated protects the recipient. Still, several infectious-disease researchers contacted by The New York Times cautioned that it would be months before enough people in the United States will have gotten the shots to allow for normal life to begin again.
Only then will the number of people with immunity — those who have had the disease and recovered, plus those who have been vaccinated — be large enough to take the wind out of the pandemic, said Jeffrey Shaman, an epidemiologist at Columbia who shared his team’s modeling calculations.
Dr. Shaman estimates that more than 105 million people have already been infected across the U.S., well above the number of cases that have been reported. And his projections show millions more infections are yet to come as the vaccine rolls out.
Social distancing, masking and other measures should remain in place until late July, “and that may be optimistic,” said Dr. Shaman. Otherwise, yet another resurgence of the virus is possible…
The model takes into account factors like the speed and order of vaccine distribution, the effectiveness of the vaccine after one and two doses, current social distancing measures and the transmissibility of the virus. It assumes that groups like health care workers and older adults will be prioritized according to C.D.C. guidelines, and vaccination will continue at a pace ramping up to five million doses per week…
Lauren Ancel Meyers, a professor of biology and statistics at the University of Texas at Austin, said that Dr. Shaman’s reasoning “all makes intuitive sense.” Dr. Meyers said she agreed that the uncontrolled outbreaks in many places in 2020 have lowered the benefits of a vaccine.
“Unfortunately, we’ve let this virus spread extensively and are launching the vaccination campaign at the height of the threat,” Dr. Meyers said. “The more the virus spreads before the vaccine reaches people, the fewer deaths we can prevent with the vaccine.” (B)
- B.Why Vaccines Alone Will Not End the Pandemic, By Matthew Conlen, Denise Lu and James GlanzJan, https://www.nytimes.com/interactive/2021/01/24/us/covid-vaccine-rollout.html?referringSource=articleShare